Refrigerating apparatus



Oct. 25, 1932. H, l H 1,884,317

REFRIGERATING APPARATUS Filed Sept. 30, 1929 /8 uay c g i i lll INVENTOR/a f aw. a. ///.s ATTORNEYS Patented Oct. 25, 1932 UNITED STATES PATENTOFFICE HARRY F. SMITH, OF DAYTON, OHIO, ASSIGNOR TO FRIGIDAIRECORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE BEFRIGERATINGAPPARATUS Application filed September 80, 1929.. Serial No. 398,229.

The present invention relates to refrigerating systems and particularlyto systems of the type in which a fluid other than the refrigeratingmedium is contained therein. In that type of system, this fluid iscarried with the re rigerating medium and at times an excessive quanitythereof accumulates in such parts of the system where it will hinder theoperation thereof or will cause parts of the system 19 to be destroyed.

One of the objects of the present invention is to provide for positivereturn of the fluid to its proper place within the s stem.

In the s ecific embodiment have illustrated the invention in connectionwith a refrigerating s stem of the compressor-condenser-expan er type inwhich a quantity of lubricant is contained within the system. It is amore specific object of the present invenso tion to provide positive andregular circulation of lubricant in refrigerating systems, and moreparticularly it is an object of the inventon to separate the lubricantfrom liquid refri erant within the evaporator and to reu turn it to thecompressor of a refrigerating system.

More specifically it is an object of the invention to utilize thevelocity of gaseous refrigerant in a refrigerating system for oper- 90sting a means WlllCh returns oil'from the eva orator to the compressorthereof.

urther objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing, wherein a preferred form of the invention 15 clearly shown.

In the drawing:

Fig. 1 is a diagrammatic view showing a refrigerating system having myinvention embodied there n;

Fig. 2 is a vertical longitudinal section through a portion of theevaporator of such system;

Fig. 3 is a fragmentary top plan view taken on the lines 3-3 of Fig. 2;and

Fig. i is a sectional view taken on the lines H of Fig. 2.

For the urpose of illustrating the present invention have shown in Fig.1 a compressor-condenser-expander type of refrigerating system having anevaporator 10 and acondensing element including a compressor 11, acondenser 12 and a receiver of liquid refrigerant tank 13. Refrigerantvapor is withdrawn from the evaporator through the vapor or low pressureconduit 14 and is liquetied in the condenser 12 and returned to theevaporator through the liquid or high pressure conduit 15. Thecompressor is operated by a motor 17 controlled by an automatic switch18 wh ch may be actuated in response to the refrigerating demand, forexample by a pressure responsive device 19 connected to the low pressureconduit 14.

Referring to Fig. 2, evaporator 10 comprises a header 20 forming areservoir for iquid refrigerant, and a plurality of tubes or ducts 21depending from the header 20 for circulating refrigerant. The liquidrefrigerant indicated by 22 is kept at a constant level 23 by a valve 24actuated by a float 25. The liquid refrigerant is supplied by aconnection 15a and the vapor or gaseous refrigerant is withdrawn througha connection 14a connected to the vapor conduit 14.

The ap aratus, or system, as generally described a ove may be altered tosuit conditions. Such systems, if of the compressor type, may belubricated by placing a quantity of Oil in the crankcase and dependingupon the splashing of the rotating parts to distribute the oilthroughout the compressor. Some of the oil is dissolved in therefrigerant and some of the oil is mechanically pumped by the compressorto the condenser and receiver and eventually to the evaporator. Therefrigerant boils oil in the evaporator, leaving the oil, which collectsin a layer of from inch to 1 4 inches thick on tog of the refrigerant.

rouble has been experienced in the past because oil could not beseparated from the liquid refrigerant and removed from the evaporatoreifectively. This accumulation of oil in the evaporator exhausts thesupply of lubricant in the compressor thereby causing shaft seals tosqueak and the bearings to be ruined. The large quantity of oilcollected in the evaporator also cools and becomes very viscous therebyhindering evaporation of the refrigerant. This is particularly harmfulwhen the system is used to refrigerate an ice cream cabinet or the likewherein very low temperatures are desired to be maintained.

My invention is directed to a system whereby the circulation of oiltherein will be positive and regular. In the particular application, Iprovide a device which utilizes the difference in viscosity, or the rateof flow over a wetted surface, of liquid refrigerant and lubricant toseparate one from the other so that the lubricant, which is greater inviscosity, will adhere to the device and will be separated from therefrigerant within the evaporator and conveyed to the outlet thereof.The oil extracted from the layer is then discharged into the vaporoutlet conduit within the evaporator and is returned to the compressoralong with gaseous refrigerant.

A conduit 30 projecting into the header 20 of the evaporator 10 isprovided with a refrigerant gas inlet opening 31 located considerablyabove the level of the liquid refrigerant within the header to preventthe entrance of liquid refrigerant into this opening. The portion of theconduit immediately surrounding the inlet opening 31 extends outwardlytherefrom and has a scraper 32 formed at its end. The portion of the comduit between the scraper 32 and the opening 31 is formed to provide atrough 33. Two legs 34 soldered or welded onto the conduit 30 serve asbearings for receiving a pin 35 which carries a disk-like wheel 36. Theouter rim of the wheel 36 and a portion of its sides extend into thelayer of oil on top of the liquid refrigerant contained in the headerand communicates with the scraper 32. A worm gear 37 secured to thewheel 36 engages a worm'38 which is mounted on a shaft 39 carrying a fanor turbine 40. The turbine 40 is enclosed within a circular extension 41formed in the conduit 30. venturi like orifice 42 is formed in theconduit 30 at the connection of the circular extended portion 41.

In the operation of the system, compressor 11 and condenser 12 liquefythe refrigerant which is collected in the liquid receiver 13 togetherwith lubricant passing from the compressor. The liquid refrigeranttogether with dissolved. lubricant are admitted by means of the floatvalves 24 into the evaporator 10, and, as the refrigerant is evaporated,the gaseous refrigerant is returned through the conduit 30, connection14a and conduit 14 to the compressor 11. The oil in evaporator 10 floatson top of the liquid refrigerant after it has separated from the liquidrefrigerant by concentration through the constant evaporation of therefrigerant. The layer of oil on top of the refrigerant in theevaporator will at times also contain all globules of liquid refrigerantdue to .1 constant boiling and eruption of the refrigerant through theoil film. This necessitates absolute separation of the lubricant fromthe refrigerant before the lubricant can be conveyed to the outlet ofthe evaporator. Under the conditions of operation suction produced bythe compressor creates a flow of gaseous refrigerant through the conduit30. The venturi like orifice 42, provided in the conduit 30, increasesthe velocity of the gaseous refrigerant and causes rapid rotation of theturbine 40. The turbine 40 actuates the shaft 39 and the worm 38, whichmeshes with the worm gear 37 provided on wheel 36, and causes the wheelto rotate. The speed of the wheel 36 is computed with respect to therelative viscosity of the liquid refrigerant and lubricant so thatrevolutions of the wheel is such that the lubricant will cling or adherethereto during its operation while the liquid refrigerant will bevaporized or will flow from the wheel back into the body of liquidcontained in the header. The lubricant is thus separated from the liquidrefrigerant and is conveyed by the wheel to the scraper 32 which removesthe lubricant therefrom and deposits it in the troughportion 33 of theconduit 30. The conduit 30 then directs this oil into the inlet opening31 of the conduit 30 from where it is returned to the crankcase of thecompressor 11 along with the gaseous refri erant. Should any liquidrefrigerant be sp ashed into the conduit 30 during violent boilingwithin the header it will readily distill into a gaseous state due tothe mass of metal comprising the conduit which is connected with the endplate of the header through which heat is conducted to the conduit.Therefore only gaseous refrigerant along with lubricant, which entersthe suction line 14, will be returned to the compressor. This preventsfrosting of the conduit 14 which ordinarily occurs by the suction ofliquid refrigerant into the conduit. It is apparent that the parts justdescribed and particularly the operation of the rotating wheel 36provides a mechanical moving device or means, that is, a means capableof mechanical operation or action which is actuated in response to theflow of refrigerant through a portion of the system or through theoutlet of the evaporator for separating lubricant from the refrigerantand for returning lubricant to the compressor by utilizing thedifference in viscosity or the difference in rate of flow by gravity ofthe two liquids.

From the foregoing it is apparentthat I have provided an apparatus whichis infallible in its action and which functions more efficiently whenthe evaporator is endeavoring to maintain a very low temperature whichlow temperature increases the viscosity of the lubricant while at thesame time increasing the adhesion thereof to the wheel utilized forextracting the lubricant from the evaporator. My improved apparatusinsures a positive Jfl and regular circulation of oil contained in therefrigerating system. With this accomplished evaporators of the typedisclosed are prevented from becoming oil-logged and are therefore moreefiicient for producing very low temperatures. Likewise the life of thecompressor bearings are prolonged and the compressor shaft seal isprevented from squeaking.

While the form of embodiment of the present invention as hereindisclosed, constitutes a preferred form, it is to be understood that oter forms might be adopted, all coming within the scope of the claimswhich follow.

What is claimed is as follows:

1. A refrigerating system containing a quantity of refrigerant andlubricant, circulating means forthe refrigerant, revolving meansactuated by the How of refrigerant in a portion of the system forcausing circulation of lubricant therein.

2. A refrigerating system comprising in combination, a refrigerantcircuit having low pressure and high pressure sides, said circuitcontaining a quantity of refrigerant and lubricant, revolving meansactuated by the flow of refrigerant in the low pressure side for causingcirculation of lubricant through said circuit.

3. A refrigerating system comprising in combination, a refrigerantcircuit containin a quantity of refrigerant and another fluid andincluding a low pressure and a high pres sure side, means communicatingwith the circuit for circulating refrigerant therein, and revolvingmeans actuated by the flow of refrigerant in the low pressure side forcausing circulation of the other fluid contained in said circuit.

4. A refrigerating system comprising in combination, a refrigerantcircuit having low pressure and high pressure sides, an evaporator, saidevaporator contaimng a quantity of refrigerant and lubricant and havinganinlet and an outlet connected with the circuit, revolving meansassociated with the outlet of said evaporator for withdrawing lubricantfrom the evaporator to cause its circulation through said circuit.

5. A refrigerating systemincluding a compressor and an evaporator, saidevaporator aving an outlet, conduit means connecting said outlet withsaid compressor, a revolving wheel within the evaporator for conveyinglubricant to the outlet thereof.

6. A refrigerating system including a compressor and an evaporator, saidevaporator having an outlet connection and containing a quantity ofliquid refrigerant and lubricant, an inwardly extending conduitcommunicating with said outlet and having an opening, a revolving wheeladapted to convey lubricant toward the opening of said conduit to causeits return to the compressor.

7. A refrigerating system including a compressor and an evaporator, saidevaporator having an outlet connection and containing a quantity ofliquid refrigerant and lubricant, an inwardly extending conduitcommunicat; ing with said outlet, a wheel cooperating with said conduitadapted to discharge lubricant into the conduit to cause its return tothe compressor, and means actuated by the flow of refrigerant from theevaporator for rotating said Wheel.

8. A refrigerating system including a compressor and an evaporator, saidevaporator having ,an outlet connection and containing a quantity ofliquid refrigerant and lubricant, an inwardly extending conduitcommunicating with said outlet, a wheel cooperating with said conduitadapted to discharge lubricant into the conduit to cause its return tothe compressor, and means located within the conduit actuated by theflow of refrigerant from the evaporator for rotating said wheel.

9. A refrigerating system including a compressor and an evaporator, saidevaporator having an outlet connection and containing a quantity ofliquid refrigerant and lubricant, an inwardly extending conduitcommunicating with said outlet connection and having an opening, a wheelcooperating with said conduit adapted to discharge lubricant into theconduit opening to cause its return to the compressor, means actuated bythe flow of refrigerant through said conduit for rotating said wheel,and means for increasing the ve locity of the refrigerant flowingthrough said first means.

10. A refrigerating system including a compressor and an evaporator,said evaporator having an outlet connection and containing a quantity ofliquid refrigerant and lubricant, an inwardly extending conduitcommunicating with said outlet connection and having an opening, a wheelcooperating with aid conduit adapted to discharge lubricant into theconduit opening to cause its return to .said wheel, saidiconduithaving aventuri like orifice for increasing the velocity of the refrigerantflowing through said actuating means.

11. A refrigerating system including a compressor and an evaporator,said evaporator having an outlet connection and containing a quantity ofliquid refrigerant and lubricant, an inwardly extending conduitcommunicating with said outlet connection and having an opening, a wheelcooperating with said conduit adapted to discharge lubricant into theconduit opening to causeits return to the compressor, a turbine actuatedby the flow of refrigerant through said conduit for rotating said Wheel,and means for increasing the velocity of the refrigerant flowing throughsaid turbine.

12. A refrigerating system including a compressor and an evaporator,said evaporator having an outlet connection and containing a quantity ofliquid refrigerant and lubricant, an inwardly extending conduitcommunicating with said outlet connection and having an opening, ascraper adjacent the opening in saidconduit, a wheel cooperating withsaid scraper adapted to discharge lubricant into the conduit opening tocause its return to the compressor, and means actuated by the flow of refrigerant through said conduit for rotating said wheel.

13. A refrigerating system including a compressor and an evaporator,said evaporator having an outlet connection and containing a quantity ofliquid refrigerant and lubricant, an inwardly extending conduitcommunicating with said outlet connection and having an opening, ascraper adjacent the opening in said conduit, a wheel cooperating withsaid scraper adapted to discharge lubricant into the conduit opening tocause its return to the compressor, means actuated by the flow ofrefrigerant through said conduit for rotating said wheel, and means forincreasing the velocity of the refrigerant flowing through said firstmeans.

14:. An evaporator of a refrigerating system having an outlet andcontaining a quantity of liquid refrigerant and lubricant, mechanicalmoving means utilizing the difference in viscosity of the liquidrefrigerant and lubricant on said mechanical moving means for separatingthe lubricant from the refrigerant and for conveying said lubricant tothe outlet of the evaporator, said mechanical moving means beingactuated by the flow of refrigerant through the outlet of theevaporator.

15. An evaporator of a refrigerating system havin an outlet andcontaining a quantity of I liquid refrigerant and lubricant, meansincluding a Wetted surface utilizing the difference in rate of flow bygravity on the Wetted surface of the liquid refrigerant and lubricantfor separating the lubricant from the refrigerant and for conveying saidlubricant to the outlet of the evaporator.

16. A refrigerating system containing a quantity of refrigerant andanother fluid and including an evaporator, said evaporator having acontinuously open outlet, circulating means for the refrigerant,mechanical moving means actuated by the flow of refrigerant through saidcontinuously open outlet for causing circulation of the other fluidcontained in the system.

17. A refrigerating system containing a quantity of refrigerant andlubricant and including an evaporator, said evaporator hav ing acontinuously open outlet circulating means for the refrigerant,mechanical moving means actuated by the liowof refrigerant through saidcontinuously open outlet for causing circulation of lubricant throughsaid system.

18. A refrigerating system containing a quantity of refrigerant andanother liquid, circulating means for the refrigerant, mechanical movingmeans actuated by the flow of refrigerant in a portion of the system forcausing circulation of the other liquid contained in the system byutilizing the difference in rate of flow by gravity of the refrigerantand the other liquid on said mechanical moving means.

19. An evaporator of a refrigerating system having an outlet andcontaining a quantity of liquid refrigerant and lubricant, mechanicalmoving means utilizing the diffcrence in rate of flow by gravity of theliquid refrigerant and the lubricant on said mechanical moving means forseparating the lubricant from the liquid refrigerant and for conveyingsaid separated lubricant to the outlet of the evaporator, saidmechanical moving means being actuated by the flow of refrigerantthrough the outlet of the evaporator.

20. A refrigerating system including a compressor, a condenser, and anevaporator operatively connected together, a body of liquid in saidevaporator, revolving means communicating with said body of liquid insaid evaporator, said revolving means being actuated by the flow offluid from the evaporator to the compressor for causing circulation ofthe liquid contained in said evaporator.

In testimony whereof I hereto afiix my signature.

HARRY F. SMITH.

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